"CRUDE, boorish and slow- witted" - even dictionaries give Neanderthals a hard time. But our prehistoric cousins were in reality just as smart as we are and did not die out as a result of a lack of brain power, according to a new archaeological study.

Until now, the leading theory of why the Neanderthals disappeared has been that a lack of intelligence meant they were less efficient hunters.

But a team of US archaeologists believe they met their evolutionary end because of a failure to maintain social links with other groups, unlike modern humans, who travelled widely, making the friends who would help them during hard times.

Working in the Caucasus region of modern-day Georgia, the scientists discovered evidence of highly skilled hunting behaviour by the Neanderthals that required an understanding of yearly animal migration patterns and the planning of traps to catch them.

But they also found there was a crucial difference between Neanderthals and homo sapiens. The Neanderthals tended to be anti-social, staying in small hunter-gatherer groups, while the sapiens were "routinely" travelling distances of 60 miles and meeting other groups.